The compounds of the invention and the pharmaceutically acceptable acid-addition salts thereto relate to and are useful as active ingredients for pharmaceuticals, especially for topical administration. Similar compounds have been used in the treatment of acne and psoriasis, as well as for inflammatory and allergic dermatoses. The compounds of the invention are useful in such treatments and are distinguished in particular by a good tolerance, for example by the absence of skin irritations on topical administration.
The compounds of the invention have the general formula: ##STR1## wherein R.sup.1 represents a group of the formula --CH.sub.2 OH, --CH.sub.2 OR.sup.6, --COR.sup.7 or --CONH.sub.2 ; R.sup.2 represents hydrogen or lower alkanoyl; R.sup.3 and R.sup.4 represent hydrogen or lower alkanoyl or a group R.sup.6 ; R.sup.5 represents lower alkoxy or a group OR.sup.6 or OR.sup.8 ; R.sup.6 represents p-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)propenyl]-benzoyl; R.sup.7 represents hydroxy, lower alkoxy or OM in which M represents a cation; and R.sup.8 represents p-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)-propenyl]benzyl, provided that (i) R.sup.1 represents a group of the formula --CH.sub.2 OR.sup.6, R.sup.2 represents hydrogen and one of R.sup.3 and R.sup.4 represents hydrogen and the other represents a group R.sup.6 when R.sup.5 represents lower alkoxy; (ii) R.sup.1 represents a group of the formula --COR.sup.7 and R.sup.2, R.sup.3 and R.sup.4 represent lower alkanoyl when R.sup.5 represents a group of the formula OR.sup.6 ; or (iii) R.sup.1 represents a group of the formula --CH.sub.2 OH, --COR.sup.7 or --CONH.sub.2 and R.sup.2, R.sup.3 and R.sup.4 represent hydrogen or lower alkanoyl when R.sup.5 represents a group of the formula OR.sup.8.